Effect of magnesium doping on NiO hole injection layer in quantum dot light‐emitting diodes
Nayoon Lee, Van Khoe Vo, Hyo-Jun Lim, Sunwoo Jin, Thi Huong Thao Dang, Heewon Jang, Dayoung Choi, Joon‐Hyung Lee, Byoung-Seong Jeong, Young-Woo Heo
Abstract
Abstract This study reports on the fabrication of quantum dot light‐emitting diodes (QLEDs) with an ITO/Ni 1− x Mg x O/SAM/TFB/QDs/ZnMgO/Al structure and investigates the effects of various Mg doping concentrations in NiO on device performance. By doping Mg into the inorganic hole‐injection layer NiO (Ni 1− x Mg x O), we improved the band alignment with the hole‐injection layer through band tuning, which enhanced charge balance. Optimal Mg doping ratios, particularly a Ni 0.9 Mg 0.1 O composition, have demonstrated superior device functionality, underscoring the need for fine‐tuned doping levels. Further enhancements were achieved through surface treatments of Ni 0.9 Mg 0.1 O with UV‐Ozone (UVO) and thermal annealing (TA) of the ZnMgO electron transport layer. Consequently, by optimizing Mg‐doped NiO in QLED devices, we achieved a maximum external quantum efficiency of 8.38 %, a brightness of 66,677 cd/m 2 , and a current efficiency of 35.31 cd/A, indicating improved performance. The integration of Mg‐doped NiO into the QLED structure resulted in a device with superior charge balance and overall performance, which is a promising direction for future QLED display technologies.